Hybrid storage system and method of operating the same

ABSTRACT

An energy storage system including a thermal energy storage apparatus configured to store thermal energy, an electrical energy storage apparatus configured to electrical energy, and a controller including a memory and an electronic processor. The controller is configured to monitor one or more characteristics of at least one selected from the group consisting of the thermal energy storage apparatus and the electrical energy storage apparatus. The controller is further configured to control, based on the one or more characteristics, the electrical energy storage apparatus to provide electrical energy to the thermal energy storage apparatus

RELATED APPLICATIONS

This application claims the benefit to U.S. Provisional Patent Application No. 62/491,906, filed on Apr. 28, 2017, the entire contents of which are incorporated herein by reference.

FIELD

Embodiments relate to a system and method of storing electrical and thermal energy.

SUMMARY

As energy costs rise, electrical energy storage solutions are being sought. Electrical energy storage solutions may include one or more rechargeable batteries that are configured to store energy during off-peak hours (for example, when energy prices are at the lowest during the day). Such electrical energy storage solutions may be expensive, as well as inefficient (for example, some may have an efficiency of approximately 80%).

Thus, one embodiment provides an energy storage system including a thermal energy storage apparatus configured to store thermal energy, an electrical energy storage apparatus configured to electrical energy, and a controller including a memory and an electronic processor. The controller is configured to monitor one or more characteristics of at least one selected from the group consisting of the thermal energy storage apparatus and the electrical energy storage apparatus. The controller is further configured to control, based on the one or more characteristics, the electrical energy storage apparatus to provide electrical energy to the thermal energy storage apparatus.

Another embodiment provides a method of supplying energy to a thermal energy storage apparatus, configured to store thermal energy, and an electrical energy storage apparatus, configured to electrical energy. The method includes monitoring one or more characteristics of at least one selected from the group consisting of the thermal energy storage apparatus and the electrical energy storage apparatus. The method further includes controlling, via a controller, the electrical energy storage apparatus to provide electrical energy to the thermal energy storage apparatus, wherein the electrical energy storage apparatus is controlled based on the one or more characteristics.

Embodiments described herein may have benefits including lower cost (most homes already own at least one thermal energy storage apparatus (for example, a water heater)), as well as improved efficiency (for example, efficiency of approximately 95%).

Other aspects of the application will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an energy system according to some embodiments

FIG. 2 is a partial cutaway view of a thermal energy storage device of the energy system of FIG. 1 according to some embodiments.

FIG. 3 is a block diagram of the thermal energy storage device of FIG. 2 according to some embodiments.

FIG. 4 is a block diagram of an electrical energy storage device of the energy system of FIG. 1 according to some embodiments.

FIG. 5 is a block diagram of a main computer of the energy system of FIG. 1 according to some embodiments.

FIG. 6 is a flowchart illustrating an operation of the energy system of FIG. 1 according to some embodiments.

FIGS. 7A & 7B are graphs illustrating power usage in the energy system of FIG. 1 according to some embodiments.

FIG. 8 is a flowchart illustrating an operation of the energy system of FIG. 1 according to some embodiments.

FIGS. 9A & 9B are block diagrams illustrating an electrical energy system according to some embodiments.

DETAILED DESCRIPTION

Before any embodiments of the application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The application is capable of other embodiments and of being practiced or of being carried out in various ways.

FIG. 1 illustrates an energy system 100 according to some embodiments. The energy system 100 includes a thermal energy storage apparatus 105, an electrical energy storage apparatus 110, and a main computer 115. In illustrated embodiment, the main computer 115 is electrically and/or communicatively coupled to the thermal energy storage apparatus 105 and the electrical energy storage apparatus 110 via communication links 120, 125. In some embodiments, communication links 120, 125 are wireless communication links. In other embodiments, communication links 120, 125 are wired communication links.

In the illustrated embodiment, the thermal energy storage apparatus is configured to receive electrical energy (i.e., power) from the electrical energy storage apparatus 110 and/or the utility 130. The electrical energy storage apparatus 110 may receive power from the utility 130. The electrical energy storage apparatus 110 may output power to the thermal energy storage apparatus 105 and/or a user 135. Additionally, the user 135 may receive power from the utility 130. In some embodiments, the electrical energy storage apparatus 110 includes one or more batteries (for example, rechargeable batteries having a lithium-ion or similar chemistry). For example, the one or more batteries may be a first battery and a second battery. In other embodiments, the electrical energy storage apparatus 110 include one or more capacitors (for example, super capacitors). For example, the one or more capacitors may be a first capacitor and a second capacitor.

In some embodiments, the utility 130 is a grid, or a power grid, for example but not limited to, an energy company power grid or a home power grid including solar panels, windmills, or other energy sources. In some embodiments, the user 135 may include the actual user (receiving thermal energy) and/or a residential single family power network used by the user 135, a residential multi-family power network used by the user 135, a commercial power network used by the user 135, and/or one or more device (for example, electrical devices) used by the user 135. In some embodiments, the user 135 may include one or more users and/or one or more electrical user devices.

FIG. 2 illustrates the thermal energy storage apparatus 105 according to some embodiments. The thermal energy storage apparatus 105 is configured to store thermal energy. In some embodiments, the thermal energy storage apparatus 105 is configured to convert electrical energy into thermal energy. As illustrated, in some embodiments, the thermal energy storage apparatus 105 may be a water heater, such as but not limited to an electric water heater, a heat pump water heater, and/or a hybrid water heater having an electric heating element and a heat pump. In some embodiments, the thermal energy storage apparatus 105 may include one or more water heaters.

In the embodiment illustrated in FIG. 2, the thermal energy storage apparatus 105 may include an enclosed tank 200, a shell 205 surrounding the water tank 200, and foam insulation 210 filling an annular space between the water tank 200 and the shell 205. The tank is configured to hold a fluid, such as but not limited to water. The tank 200 may be formed of ferrous metal and lined internally with a glass-like porcelain enamel to protect the metal from corrosion. In other embodiments, the water tank 200 may be formed of other materials, such as plastic.

A water inlet line 215 and a water outlet line 220 may be in fluid communication with the water tank 200 at a top portion of the thermal energy storage apparatus 105. The inlet line 215 may have an inlet opening 225 for adding cold water to the water tank 200, and the outlet line 220 may have an outlet opening 230 for withdrawing hot water from the water tank 200. The inlet line 215 and the outlet line 220 may be in fluid communication with a mixing valve 235. The mixing valve 235 may combine water from both the inlet line 215 and the outlet line 220 in order to output water at a delivery temperature set point. In some embodiments, the mixing valve 235 may include electrical and electronic components configured to set the delivery temperature set point. For example, but not limited to, a controller and a sensor (e.g., a water temperature sensor).

The thermal energy storage apparatus 105 may also include one or more heating elements, for example, an upper heating element 240 and a lower heating element 245 that may be attached to the water tank 200 and may extend into the water tank 200 to manipulate a temperature of the fluid. Each heating element 240,245 may be an electric resistance heating element or another type of heating element. In some embodiments, the upper heating element 240 may heat an upper portion (e.g., the upper one-third) of the water in the water tank 200 and the lower heating element 245 may heat a lower portion (e.g., the lower two-thirds) of the water in the water tank 200. Although in the illustrated embodiment, two heating elements 240, 245 are shown, any number of heating elements may be included in the thermal energy storage apparatus 105.

The thermal energy storage apparatus 105 may also include one or more temperature sensors 250, 255. In some embodiments, the thermal energy storage apparatus 105 may include more or less temperature sensors. In the illustrated embodiment, temperature sensor 250 is an upper temperature sensor and temperature sensor 255 is a lower temperature sensor. Additionally, in some embodiments, temperature sensor 250 is positioned proximate the upper heating element 240 and temperature sensor 255 is positioned proximate lower heating element 245. The temperature sensors 250, 255 may be in contact with the water tank 200 walls, and may be, for example, thermistor-type sensors. In the embodiment shown, temperature sensors 250, 255 may be used to control the upper and lower heating elements 240, 245.

The thermal energy storage apparatus 105 may also include the thermal control system 300. The thermal control system 300 may be attached to the thermal energy storage apparatus 105 (e.g., within, outside of, or on top of the shell 205), located remotely from the thermal energy storage apparatus 105, or a combination thereof. The thermal control system 300 may be one system or numerous systems working together.

In other embodiments, the thermal energy storage apparatus 105 may be to or more water heaters. In yet other embodiments, the thermal energy storage apparatus 105 may be any device configured to store thermal energy, such as but not limited to, a furnace, an air-conditioning unit, a refrigerator, an oven, and/or a combination of thermal energy storage devices.

FIG. 3 is a block diagram of the thermal control system 300 according to some embodiments. The thermal control system 300 includes a controller 305, a relay 310, and a communications module 315. The controller 305 includes an electronic processor 320 and memory 325. The memory 325 stores instructions executable by the processor 320. In some instances, the controller 305 includes one or more of a microprocessor, digital signal processor (DSP), field programmable gate array (FPGA), application specific integrated circuit (ASIC), or the like. The controller 305 is electrically and/or communicatively coupled to relay 310, the communications module 315, and the sensors 250, 255.

The relay 310 selectively provides power (i.e., electrical energy) to heating elements 240, 245. The relay 310 may include, among other things, electrical contacts. Upon receiving a signal from controller 305, the relay 310 places the contacts together so that power may flow to the heating elements 240, 245. As discussed above, the power provided to the heating elements 240, 245, via the relay 310, may come from the electrical energy storage apparatus 110 and/or the utility 130.

The communications module 315 provides communication between the thermal energy storage apparatus 105 and other devices (for example, the electrical energy storage apparatus 110 and the main computer 115). In some embodiments, the communication is provided through a network. In such an embodiment, the network is, for example, a wide area network (WAN) (e.g., the Internet, a TCP/IP based network, a cellular network, such as, for example, a Global System for Mobile Communications [GSM] network, a General Packet Radio Service [GPRS] network, a Code Division Multiple Access [CDMA] network, an Evolution-Data Optimized [EV-DO] network, an Enhanced Data Rates for GSM Evolution [EDGE] network, a 3GSM network, a 4GSM network, a Digital Enhanced Cordless Telecommunications [DECT] network, a Digital AMPS [IS-136/TDMA] network, or an Integrated Digital Enhanced Network [iDEN] network, etc.). In other embodiments, the network is, for example, a local area network (LAN), a neighborhood area network (NAN), a home area network (HAN), or personal area network (PAN) employing any of a variety of communications protocols, such as Wi-Fi, Bluetooth, ZigBee, etc. In yet another embodiment, the network includes one or more of a wide area network (WAN), a local area network (LAN), a neighborhood area network (NAN), a home area network (HAN), or personal area network (PAN).

FIG. 4 is a block diagram of the electrical energy storage apparatus 110 according to some embodiments. The electrical energy apparatus 110 is configured to receive, store, and/or output electrical energy. In some embodiments, the electrical energy apparatus 110 may be configured to receive, store, and/or output electrical energy when electrical usage behind a user's electric meter is less than an amount of energy to be shed. As illustrated the electrical energy storage apparatus 110 includes a controller 400, an electrical input 405, an inverter, or converter, 410, an energy storage device 415, a communications module 420, and one or more electrical outputs 425. The controller 400 may include an electronic processor 430 and memory 435. The memory 435 stores instructions executable by the electronic processor 430. In some instances, the controller 400 includes one or more of a microprocessor, digital signal processor (DSP), field programmable gate array (FPGA), application specific integrated circuit (ASIC), or the like. The controller 400 is electrically and/or communicatively coupled to the inverter 410, the energy storage device 415, and the communications module 420.

The electrical input 405 receives, and provides, power from the utility 130 to the inverter 410. The inverter 410 is configured to convert, or invert, power from the utility 130 to a converted power. In some embodiments, the inverter 410 converts alternating-current voltage to direct-current voltage. The converted power is then supplied to the energy storage device 415. The energy storage device 415 is configured to store electrical energy. In some embodiments, the energy storage device 415 includes one or more batteries, such as but not limited to one or more rechargeable batteries. In some embodiments, the one or more batteries may have a lithium-ion chemistry, while in other embodiments, the batteries may have a chemistry other than lithium-ion such as, for example, nickel-cadmium, nickel metal-hydride, etc. Additionally or alternatively, the batteries may be non-rechargeable batteries. In yet another embodiment, the energy storage device 415 may include one or more capacitors.

Power from the energy storage device 415 may selectively be output (via electrical output 425 a, 425 b) to the thermal energy storage apparatus 105 and/or the user 135. In some embodiments, power output from the energy storage device 415 may be supplied to the thermal energy storage apparatus 105 before a user's electric meter. In other embodiments, power output from the energy storage device 415 may be supplied to the thermal energy storage apparatus 105 after a user's electric meter.

The communications module 420 provides communication between the electrical energy storage apparatus 110 and other devices (for example, the thermal energy storage apparatus 105 and the main computer 115). In some embodiments, the communication is provided through the network.

FIG. 5 is a block diagram illustrating the main computer 115 according to some embodiments. In the illustrated embodiment, the main computer 115 includes a controller 500 electrically and/or communicatively coupled to a communications module 505 and one or more sensors 510. Similar to controllers 305, 400, the controller 500 may include an electronic processor 515 and memory 520. The memory 520 stores instructions executable by the electronic processor 515. In some instances, the controller 500 includes one or more of a microprocessor, digital signal processor (DSP), field programmable gate array (FPGA), application specific integrated circuit (ASIC), or the like. In some embodiments, the main computer 115 is implemented, at least partially, into controller 305 and/or controller 400.

The communications module 505 is configured to provide communication between the main computer 115 and the thermal energy storage apparatus 105 and/or the electrical energy apparatus 110. In some embodiments, the communications module 505 is further configured to provide communication between the main computer 115 and an external computer (for example, an external grid computer, a power aggregator, a user device (e.g., a smartphone, a tablet, a personal computer), etc.). In some embodiments, the communications module 505 provides communication through the network.

The one or more sensors 510 are configured to one or more characteristics of the thermal energy storage apparatus 105, the electrical energy apparatus 110, the utility 130, and/or the user 135. The one or more sensors 510 may be located within, or proximate, the thermal energy storage apparatus 105, the electrical energy apparatus 110, the main computer 115, and/or a location of the user 135. The one or more sensors 510 may include, but is not limited to, a power sensor (for example a current sensor, a voltage sensor, an electrical usage sensor, etc.), an occupancy sensor (for example, a video camera, a laser sensor, a door sensor, etc.), a temperature sensor (for example, sensors 250, 255, etc.), and a usage sensor (for example, a flow sensor, one or more temperature sensors, etc.).

The one or more characteristics may include a temperature of the fluid within the thermal energy storage apparatus 105, a voltage of the electrical energy storage apparatus 110, a charge capacity of the electrical energy storage apparatus 110, an occupancy of one or more users 135, a current received by the electrical energy storage apparatus 110, a current received by one or more electrical devices used by a user 135, a current received from the utility 130, and a current received by the thermal energy storage apparatus 105.

In operation, the main computer 115 analyzes the one or more characteristics and manages electricity usage of the thermal energy storage apparatus 105 and the electrical energy apparatus 110. For example, the main computer 115 may determine usage patterns of one or more users 135 and control the thermal energy storage apparatus 105 and/or the electrical energy storage apparatus 110 accordingly.

FIG. 6 is a flowchart illustrating an operation 600 of energy system 100 according to some embodiments. Operation 600 may be performed by controller 305, controller 400, and/or controller 500. It should be understood that the order of the steps disclosed in method 600 could vary. Additional steps may also be added to the control sequence and not all of the steps may be required. As illustrated in FIG. 6, the method 600 includes analyzing one or more characteristics (block 605). The method 600 further includes controlling the thermal energy storage apparatus 105 and/or the electrical energy storage apparatus 110 based on the analysis of the one or more characteristics (block 610).

FIGS. 7A & 7B are graphs illustrating power usage according to some embodiments. As illustrated in FIG. 7A, during normal power usage there is a large amount of heater usage (for example, usage of a thermal energy storage apparatus 105) during the hours of approximately six to approximately ten and then again during the hours of approximately eighteen and approximately twenty-one. This may result in a large amount of power required from the utility 130 during those time periods.

FIG. 7B illustrates shifted power usage, which may result from the control of the thermal energy storage apparatus 105 and/or the electrical energy storage apparatus 110 based on the analysis of the one or more characteristics (block 610 of FIG. 6). As illustrated in FIG. 7B, during shifted power usage the amount of power required from the utility 130 is spread over the course of a day.

FIG. 8 is a flowchart illustrating an operation 800 of energy system 100 according to some embodiments. Operation 800 may be performed by controller 305, controller 400, and/or controller 500. It should be understood that the order of the steps disclosed in method 600 could vary. Additional steps may also be added to the control sequence and not all of the steps may be required. As illustrated in FIG. 6, the method 800 includes analyzing one or more characteristics (block 805).

The method 800 further includes determining if energy needs to be transferred (block 810). In some embodiments, such a determination is made by receiving a command (for example, a shed command, an increase power demand command, a decrease power command, an enable command, a disable command, etc.). The command may be received from the external computer (for example, an external grid computer, a power aggregator, a user device (e.g., a smartphone, a tablet, a personal computer), etc.). In other embodiments, such a determination is made by analyzing the one or more characteristics (for example, by analyzing usage patterns of the one or more users 135).

When energy does not need to be transferred, the method 800 cycles back to block 805. When energy does need to be transferred, method 800 proceeds to determine if the thermal energy storage apparatus 105 is currently receiving power from the utility 130 (block 815). When the thermal energy storage apparatus 105 is not receiving power from the utility, method 800 cycles back to block 805. When the thermal energy storage apparatus 105 is receiving power from the utility, method 800 proceeds to determine if thermal energy demand is high (block 820).

When thermal energy demand is high, the electrical energy storage apparatus 110 provides power to the thermal energy storage apparatus 105 (block 825). By receiving power from the electrical energy storage apparatus 110, the load on the utility 130 is reduced, while the thermal energy storage apparatus 105 may continue to operate. Method 800 may then cycle back to block 805. When thermal energy demand is not high, power may be provided to one or more other devices (block 830). Method 800 may then cycle back to block 805.

As discussed above, the energy system 100 may be implemented in a multi-family residential building (for example, a condominium or apartment building). In such an embodiment, each unit of the building may include an individual thermal energy storage apparatus 105. In such an embodiment, the multi-family residential building may include one or more electrical energy storage apparatuses 110 configured to provide power to the thermal energy storage apparatuses 105. In other embodiments, each unit of the building may include an individual electrical energy storage apparatus 110.

FIGS. 9A and 9B are block diagrams illustrating a system 900 for use in a building having two or more units. As illustrated in FIG. 9A, during normal power is supplied from the utility 130 to the thermal energy storage apparatuses 105 a, 105 b, as well as to the electrical energy storage apparatus 110 (as needed to charge the energy storage device 415, as well as provide power as needed to user 135). As illustrated in FIG. 9B, once it is determined that a load should to be shed (for example, main computer 115 receives a shed command), power is supplied from the electrical energy storage apparatus 110 to the thermal energy storage apparatuses 105 a, 105 b. In some embodiments, the power supplied from the electrical energy storage apparatus 110 supplement power supplied from the utility 130 to the thermal energy storage apparatuses 105 a, 105 b. Furthermore, in some embodiments, when a load should be shed, the electrical energy storage apparatus 110 may only supply power to one of the thermal energy storage apparatuses (for example, 105 a), while the other thermal energy storage apparatus (for example, 105 b) is not supplied power.

In some embodiments, the system 900 will use the one or more sensors 510 to determine a real-time occupancy and/or a usage of a first user 135 a using the first the thermal energy storage apparatus 105 a and a second user 135 b using the second the thermal energy storage apparatus 105 b. The main computer 115 will then control the thermal energy storage apparatuses 105 a, 105 b and the electrical energy storage apparatus 110 based on the occupancy and/or usage. For example, the first user 135 a may not currently be using the first thermal energy storage apparatus 105 a. Therefore, the first thermal energy storage apparatus 105 a may be unable to receive and store thermal energy (for example, the first thermal energy storage apparatus 105 a may contain a fluid that is already at a maximum temperature). The main computer 115 may determine that the first thermal energy storage apparatus 105 a is unable to receive and store thermal energy, and thus control the second thermal energy storage apparatus 105 b to receive and store thermal energy, after determining that the second thermal energy storage apparatus 105 b is capable (based on the determined real-time occupancy and/or usage of the second user).

Thus, the application provides, among other things, a method and system for controlling a thermal energy storage apparatus in conjunction with an electrical energy storage apparatus. Various features and advantages of the application are set forth in the following claims. 

What is claimed is:
 1. An energy storage system comprising: a thermal energy storage apparatus configured to store thermal energy; an electrical energy storage apparatus configured to electrical energy; a controller including a memory and an electronic processor, the controller configured to monitor one or more characteristics of at least one selected from a group consisting of the thermal energy storage apparatus and the electrical energy storage apparatus, control, based on the one or more characteristics, the electrical energy storage apparatus to provide electrical energy to the thermal energy storage apparatus.
 2. The energy storage system of claim 1, wherein the thermal energy storage apparatus includes a first water heater and a second water heater.
 3. The energy storage system of claim 2, wherein the controller determines which water heater selected from a group consisting of the first water heater and the second water heater receives electrical energy from the electrical energy storage apparatus.
 4. The energy storage system of claim 1, wherein the electrical energy storage apparatus includes a first battery and a second battery.
 5. The energy storage system of claim 4, wherein the controller determines which battery selected from a group consisting of the first battery and the second battery provides electrical energy to the thermal energy storage system.
 6. The energy storage system of claim 1, wherein the thermal energy storage apparatus includes a tank configured to hold a fluid, and a heating element configured to manipulate a temperature of the fluid.
 7. The energy storage system of claim 1, wherein the electrical energy storage apparatus includes at least one selected from a group consisting of a battery, a rechargeable battery, and a capacitor.
 8. The energy storage system of claim 1, wherein the controller is further configured to receive a signal, and control, in response to receiving the signal, the electrical energy storage apparatus to provide electrical energy to the thermal energy storage apparatus.
 9. The energy storage system of claim 1, wherein the signal is received from an external computer.
 10. The energy storage system of claim 1, wherein the one or more characteristics are sensed by at least one selected from a group consisting of a power sensor, an occupancy sensor, a temperature sensor, and a usage sensor.
 11. A method of supplying energy to a thermal energy storage apparatus, configured to store thermal energy, and an electrical energy storage apparatus, configured to electrical energy, the method comprising: monitoring one or more characteristics of at least one selected from a group consisting of the thermal energy storage apparatus and the electrical energy storage apparatus; and controlling, via a controller, the electrical energy storage apparatus to provide electrical energy to the thermal energy storage apparatus, wherein the electrical energy storage apparatus is controlled based on the one or more characteristics.
 12. The method of claim 11, wherein the thermal energy storage apparatus includes a first water heater and a second water heater.
 13. The method of claim 12, further comprising determining, via the controller, which water heater selected from a group consisting of the first water heater and the second water heater receives electrical energy from the electrical energy storage apparatus.
 14. The method of claim 11, wherein the electrical energy storage apparatus includes a first battery and a second battery.
 15. The method of claim 14, further comprising determining, via the controller, which battery selected from a group consisting of the first battery and the second battery provides electrical energy to the thermal energy storage system.
 16. The method of claim 11, wherein the thermal energy storage apparatus includes a tank configured to hold a fluid, and a heating element configured to manipulate a temperature of the fluid.
 17. The method of claim 11, wherein the electrical energy storage apparatus at least one selected from a group consisting of a battery, a rechargeable battery, and a capacitor.
 18. The method of claim 11, further comprising receiving, at the controller, a signal, and controlling, via the controller, the electrical energy storage apparatus to provide electrical energy to the thermal energy storage apparatus, wherein the electrical energy storage apparatus is controlled in response to receiving the signal.
 19. The method of claim 11, wherein the signal is received from an external computer.
 20. The method of claim 11, wherein the one or more characteristics are sensed by at least one selected from a group consisting of a power sensor, an occupancy sensor, a temperature sensor, and a usage sensor. 